* Hamilton on pole in Spain
* Bottas seals Mercedes front-row lockout
* Verstappen starts third (Adds quotes)
By Alan Baldwin
Aug 15 (Reuters) - Formula One championship leader Lewis Hamilton clinched a record-extending 92nd career pole position in a Mercedes front-row lockout with team mate Valtteri Bottas at the Spanish Grand Prix on Saturday.
Six-times world champion Hamilton has won for the past three years at the Circuit de Catalunya outside Barcelona and he was quickest in all three phases of qualifying on another hot afternoon.
Red Bull's Max Verstappen, Hamilton's closest challenger in the standings, will start in third place with Mexican Sergio Perez lining up fourth for Racing Point on his return after missing two races due to COVID-19.
"Physically it's tough," Hamilton, who will be making his 150th career front-row start, said of the heat. "It's the fastest we've ever been round here so the forces through your body are pretty intense.
"The first lap was decent I guess, which did the job thankfully," added the Briton, who was 0.059 seconds quicker than Bottas on the soft tyres.
His second flying lap was slower than the first time of one minute 15.584 seconds.
"I was here with the guys until 10pm last night just looking over all the details -- how can we improve, what are the areas, particularly for the race, because these Red Bulls are super fast," added Hamilton.
The pole was his fourth of the season.
Bottas, who was on pole last year when the race was held in May, recognised the start would be his best chance of beating a team mate who has won three of five races so far this season.
"I knew it was going to be close with Lewis, as always," said the Finn. "Of course it's annoying but he did a good job. And as a team, first row."
Verstappen, 30 points behind Hamilton after winning at Silverstone last Sunday, had consistently been the closest challenger to the Mercedes pair in practice.
"It seems like I have a subscription on P3 (third)," said the 22-year-old Dutch driver, who took the first win of his F1 career at the circuit on his Red Bull debut in 2016.
Canadian Lance Stroll will start fifth with Verstappen's Thai team mate Alexander Albon sixth and the McLaren pair of Carlos Sainz and Lando Norris seventh and eighth.
Ferrari (NYSE:RACE)'s Charles Leclerc qualified ninth on another tough afternoon for team mate Sebastian Vettel, who failed to make the top-10 shootout for the second race in a row and will start 11th.
AlphaTauri's Pierre Gasly completed the top 10.
Further back, Alfa Romeo's Kimi Raikkonen had his best qualifying so far this year with 14th.